Heater/Defroster Ducts
My first choice is used parts from a swap meet or junkyard. Second choice would somebody like Dante's or one of the other resto suppliers. You might be able to adapt other hoses from non mopar brands but I dont know which or what make to use. Normally the defrost vents on the heater box are different size than each other. THe vent sizes on the dash board are the same size. Take your measurements with you if you go to the junkyard.